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2 years ago

Find the sum of the first 10 terms 40, 37, 34, 31

Mathematics

1 answer:

Bezzdna [24]2 years ago

4 0

<h3><u>Solution </u><u>:</u><u>-</u></h3>

Firstly finding common difference of the series

As we know that

• Common difference ( d ) = t₂ - t₁

→ Common difference = 37 - 40

→ Common difference = - 3

Now, as we know that

• Sn ( Sum of n terms ) = n/2 [ 2a + ( n - 1 ) d ]

Substituting n = 1. Since the sum of no. of terms is 10 . And substituting a = 40 ,since first term is 40

=> S₁₀ = 10/2 [ 2(40) + ( 10 - 1 ) -3 ]

=> S₁₀ = 5 [ 80 - 27 ]

=> S₁₀ = 5 × 53

=> S₁₀ = 265

Hence , sum of first 10 terms ( S₁₀ ) = 265

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Answer:

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Step-by-step explanation:

Given:

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Solution:

Let length be denoted by 'l'.

Also Let width be denoted by 'w'.

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Now Substituting equation 2 in equation 1 we get;

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Now we will find the root by factorizing the same we get;

$w^2-36w-40w+1440=0\\\\w(w-36)-40(w-36)=0\\\\(w-36)(w-40) =0 \\$

Now solving for each to find the value of 'w' we get;

$w-36 =0\\\\w=36\\\\also \\\\w-40=0\\\\w=40$

So We can say that;

Width = 36 m and Length = 40 m

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We know that square has all sides same.

So from the data we found we can say that if length is decreased by 4 then length and breadth(width) both will be equal.

So to find percentage decreased we will divide length to be decreased by total length and then multiply by 100.

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Then we want to have our initial investement doubled, this means:

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Now we can apply the Ln() to both sides, remember that:

Ln(e^x) = x

Then:

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